﻿@model String
@{
    Dictionary<string, object> result = new Dictionary<string, object>();

    var Classes = new List<String>();
    if (!Classes.Contains("form-control"))
    {
        Classes.Add("form-control");
    }
    result.Add("class", string.Join(" ", Classes));

    var guid = @Guid.NewGuid().ToString();
}
<script>
    var guid = "@guid";
</script>
<script src="/CommonRoot/js/tinymce/tinymce.min.js"></script>
<div id="@guid">
    @Html.TextArea("", Model, result)
</div>
<script src="/CommonRoot/js/tinymce/tinymce.config.js"></script>